1.5 cell division and protein control

Question 1

Cytoskeleton definition

Answer 1

The cell organelle which provides mechanical support, shape and the ability to control the movement of membrane bound organelles around a cell.

Question 2

What is the cytoskeleton made up of

Answer 2

Microtubules which are made up of tubulin

Question 2

Where does the cytoskeleton come from

Answer 2

The MTOC (microtubule organising centre)
Or called the centrosome

Question 3

What forms the spindle fibres in mitosis

Answer 3

Microtubules

Question 4

Mitotic index

Answer 4

The number of cells undergoing mitosis
PMAT /total cells x100

Question 5

What happens to the cytoskeleton in mitosis

Answer 5

It’s remodelled

Question 6

Cell cycle parts

Answer 6

Interphase
Mitotic phase

Question 7

Interphase sub phases

Answer 7

G1
S
G2

Question 8

Mitotic phase sub phases

Answer 8

Mitosis
Cytokinesis

Question 9

Polymerisation of tubulin

Answer 9

Where tubulin is built up into parts of the cytoskeleton

Question 10

Depolymerisation of Tubulin

Answer 10

Where the cytoskeleton is broken down into tubulin.

Question 11

G1 phase

Answer 11

A growth period where proteins and organelles are synthesised

Question 12

S phase

Answer 12

DNA is replicated for mitosis

Question 13

G2 phase

Answer 13

A second growth period where proteins and organelles for mitosis are synthesised

Question 14

Mitosis

Answer 14

Where chromosomes are separated by spindle fibres

Question 15

Cytokinesis

Answer 15

Where the cytoplasm will divide

Question 16

Mitosis stages

Answer 16

Prophase
Metaphase
Anaphase
Telophase

Question 17

Prophase

Answer 17

DNA condenses into 2 pairs of chromosomes which each contain 2 sister chromatids, the nuclear membrane breaks down and spindle fibres will attach to the chromosomes at the kinetochore

Question 18

Metaphase

Answer 18

The chromosomes will line up on the equator

Question 19

Anaphase

Answer 19

Spindle fibres depolymerise and pull sister chromatids apart, pulling chromosomes to opposite poles of the cell

Question 20

Telophase

Answer 20

Chromosomes decondense and nucearnmemebranse form at each pole.

Question 21

Microtubule function in cell cycle

Answer 21

Aligning chromosomes on equator
Separate sister chromatids
Formation of daughter nuclear membrane

Question 22

Cell cycle checkpoints

Answer 22

G1 checkpoint
G2 checkpoint
M checkpoint

Question 23

G2 checkpoint occurrence

Answer 23

End of G2

Question 23

G1 checkpoint occurrence

Answer 23

End of G1

Question 24

M checkpoint occurrence

Answer 24

between metaphase and anaphase

Question 25

G1 checkpoint purpose

Answer 25

To ensure sufficient cell growth

Question 25

G2 checkpoint purpose

Answer 25

To ensure success of DNA replication in S and ensure no damage is done to DNA

Question 26

M checkpoint purpose

Answer 26

Occurs during metaphase and controls entry to anaphase ensuring the chromosomes line up correctly on the equator. Meaning daughter cells will receive correct number of chromosomes

Question 27

G0

Answer 27

A non dividing phase which cells go into if they fail the G1 checkpoint

Question 28

Checkpoint regulating proteins

Answer 28

Cyclin dependent kinases (CDK)

Question 29

How do CDK’s regulate the phases of cell cycle

Answer 29

Cyclin proteins accumulate during the phases of cell cycle then they combine and activate cyclin dependent kinases
Then the CDK’s will phosphorylate proteins which regulate cell cycle.
If sufficient threshold of regulating proteins is reached the cell willmove onto onto the next stage of cell cycle

Question 30

Retinoblastoma

Answer 30

A protein which acts as a tumour suppressor by inhibiting transcription of genes that code for proteins in DNA replication

Question 31

What state is retinoblastoma in at G1

Answer 31

Active

Question 32

CDK’s method of moving out of G1

Answer 32

CDK’s will phosphorylate and deactivate retinoblastoma this will allow for transcription factors to bind to DNA and promote DNA replication allowing the cell to move into S

Question 33

What triggers p53

Answer 33

DNA damage

Question 34

p53 options

Answer 34

Repair
Arrest the cell cycle
Initiate apoptosis

Question 35

Uncontrolled reduction in cell cycle

Answer 35

Degenerative disease

Question 36

Proto - oncogene definition

Answer 36

A normal gene which is involved in the control of cell growth or cell division which mutates to form a tumour forming oncogene.

Question 36

What does excessive apoptosis lead to

Answer 36

Degenerative diseases

Question 36

Uncontrolled increase in the cell cycle

Answer 36

Tumour formation

Question 36

Apoptosis

Answer 36

Programmed cell death

Question 37

What does lack of apoptosis lead to

Answer 37

Tumour formation or cancer

Question 37

Types of apoptosis

Answer 37

External or internal

Question 37

Extrinsic (external) cell death

Answer 37

Lymphocytes or natural killers will send signal molecules to bind with receptors on the surface of the cell membrane.

Question 38

Intrinsic (internal) cell death

Answer 38

Factors such as DNA damage or lack of growth factor can cause p53 tumour suppressor protein to activate intrinsic apoptosis.

Question 39

Caspases definition

Answer 39

A type of protease enzyme which breaks down proteins and causes cell destruction

Question 39

What happens after apoptosis signal in apoptosis

Question 39

Other uses of apoptosis

Answer 39

To remove cells which are no longer required as development progresses, an example is fingers during metamorphosis